William Smith was born on 27th October 1854 at Pennyland House, Thurso, Scotland. At 15 he moved to Glasgow to work in his uncle's business. While there, he joined the volunteers and by 19 he had become a Lance Corporal in the 1st Lanarkshire Rifle Volunteers. The very same year he joined the church after hearing the evangelists Moody & Sankey.
By 1883 William Smith had become a Lieutenant and was teaching in the North Woodside Mission Sunday School. The boys in his Sunday School class were a challenge, and he was open to new ideas about how best to deal with them. Someone suggested that the methods used in the volunteers might be appropriate, and by this inspiration the Boys' Brigade was created.
William Smith took a leading role in the new organisation, accepting a full-time post as the first Brigade Secretary in 1887.

He worked non-stop for the movement, on two occasions even crossing the Atlantic to promote the Boys' Brigade in Canada and the U.S.A. Throughout he remained Captain of the 1st Glasgow company, rarely missing a meeting.
In 1909 William Smith was knighted by King Edward VII for his service to boys.
Sir William Smith died on 10th May 1914 after being suddenly taken ill at a Boys' Brigade meeting in London. He was buried in Glasgow.